Rats were trained at 2-4 months and at 24-26 months of age on a peak-interval timing procedure in which auditory and visual stimuli signaled two different fixed-interval schedules of reinforcement (15 and 30 s) that were presented simultaneously in a hierarchical fashion. Compared with control rats, increases in the probability of attention to the 15 s signal were observed for both the choline-supplemented and the choline-deficient rats. In contrast, an increase in attention to the 30 s signal was only observed for the choline-supplemented rats, whereas choline-deficient rats exhibited a decrease in attention that increased with age. Proportional rightward shifts in the remembered times of reinforcement emerged for the 24-26-month-old rats in the choline-deficient and control groups, but not in the choline-supplemented group. These results indicate that prenatal choline supplementation facilitates cognitive function across the lifespan, whereas prenatal choline deficiency impairs divided attention and accelerates age-related declines in temporal processing.